Bat echolocation: seeing with your ears
About this app
How a bat finds a moth in the dark: it calls in ultrasound and listens for the echo. The time there and back gives the distance (sound travels 343 m per second). Compare what people and bats can hear, then fly in: the calls get faster and faster, up to about 200 per second in the feeding buzz. Made for children aged 8 to 12.
With explain mode: an AI tutor walks you through the app, points out what matters in the scene and answers your questions.
The idea
Bats hunt insects at night. While flying they make very high sounds that we cannot hear: ultrasound. When a call hits a moth, an echo comes back. Sound travels about 343 metres per second in air. From the time until the echo arrives the bat knows how far away the moth is; the path counts twice, there and back. If a moth is 1.7 metres away, the echo returns after about 10 thousandths of a second. The common pipistrelle from our gardens calls at around 45 kilohertz, while people only hear up to about 20 kilohertz.
What the app shows
A garden at night with a bat, a moth and a tree. A call travels in slow motion as a wave to the moth, its echo comes back, and a timeline fills with the way there and the way back. The tree further away answers later. A second card shows which sounds people hear and where bat calls lie. In the “Hunting” scenario the bat flies at the moth: the calls get faster and faster, from about 10 to as many as 200 per second, the feeding buzz.
Try it together
Let your child place the moth near and far and guess beforehand when the echo will come back. Half as far means half as long. With the tree there are two echoes, and the distant one comes later. When hunting, watch the strokes at the bottom: the closer the moth, the denser the calls. “Make audible” makes it sound like a bat detector. The controls use large buttons and little text, for children aged 8 to 12.
Frequently asked questions
- How does bat echolocation work, explained simply?
- The bat makes high sounds and listens for the echo. The further away an object is, the later its echo returns. From this time and the direction of the echo the bat knows where a moth is flying, even in complete darkness.
- Why can we not hear bat calls?
- Most bat calls are ultrasound, higher than 20 kilohertz. The human ear hears up to about 20 kilohertz at most, adults often less. A bat detector makes the calls audible by converting them into lower sounds.
- What is the feeding buzz?
- In search flight a bat calls about ten times per second. Once it has found prey, it calls faster and faster as it approaches, up to about 200 times per second just before the catch. On a detector this sounds like a buzz, hence the name.
- What can my child try in the app?
- Your child places the moth in the garden with a tap, lets the bat call and sees how long the echo takes. A tree gives a second, later echo. In the hunting scenario the bat flies at the moth, and a strip shows how many calls fit into one second. A guided explanation mode walks through everything.
Subject: Elementary · Science & Society
More from Elementary · Science & Society
- States of matter
- Echo technology: parking sensor and echo sounder
- Simple electric circuits
- Pinhole Camera & Solar Eclipse
- The water cycle
A VisuApp by heyprof: interactive, free in your browser, no sign-up. What is a VisuApp? · All apps